The present invention relates to utility diagnosing equipment for diagnosing a plurality of utilities of an identical type on the basis of state values from the plurality of utilities, and also relates to an operational program for the equipment and a utility diagnosing method.
A utility such as an air conditioner is used, in many cases, together with a controller for controlling the utility. The controller has both a function of transmitting user's control instruction to the utility and a function of monitoring the state of the utility. Thus, when an abnormality takes place in the utility, the controller informs the user of the abnormality.
As disclosed in JP-B-3119046 in these years, there is proposed a method for increasing a maintenance efficiency by monitoring such a utility as mentioned above from a remote place using a typical network technique. In this method, a controller monitors the state value of the installed utility. And when the state value exceeds a preset threshold, the controller transmits a signal indicative of a sign of abnormality via a network to a host side, and thus the host side recognizes the abnormality of the utility.
In the prior art, however, as a threshold for the state value of the utility, an absolute threshold is set, not paying any consideration to an environmental change, a change with time, etc. in the utility. For this reason, the prior art has problems that the controller, in some cases, cannot recognize an abnormality in the utility even when the abnormality is true, or conversely can sometimes recognize a normality to the utility as an abnormality even when the normality is true. More specifically, when an absolute threshold is set for the operating temperature of the utility for example, the utility installed in a cold district cannot recognize an abnormally-high operating temperature for the utility as an abnormality. Meanwhile, the utility installed in a tropical district cannot recognize an abnormally-low operating temperature for the utility as an abnormality. When the utility is deteriorated with time, the deteriorated utility cannot recognize as an abnormality a state value abnormal to the deteriorated utility.